Cséplö A, Eigel L, Horváth G V, Medgyesy P, Herrmann R G, Koop H U
Botanical Institute, University of München, FRG.
Mol Gen Genet. 1993 Jan;236(2-3):163-70. doi: 10.1007/BF00277108.
Lincomycin-resistant Nicotiana plumbaginifolia plastid mutants were considered also to carry mitochondrial mutations on the basis of their ability to grow in the dark under selective conditions. To clarify the role of mitochondria, individual protoplasts of the green, lincomycin-resistant N. plumbaginifolia mutant LR400 were microfused with protoplasts of the N. tabacum plastid albino line 92V37, which possesses N. undulata cytoplasm. the production of lincomycin-resistant albino cybrid lines, with N. undulata plastids and recombinant mitochondria, strongly indicated a determining role for mitochondria in the lincomycin resistance. Sequence analysis of the region encompassing putative mutation sites in the 26S rRNA genes from the LR400 and several other lincomycin-resistant N. plumbaginifolia mutants revealed, however, no differences from the wild-type sequence. As an alternative source of the resistance of the fusion products, the N. tabacum fusion partner was also taken into account. Surprisingly, a natural lincomycin resistance of tobacco was detected, which was inherited as a dominant nuclear trait. This result compromises the interpretation of the fusion data suggested above. Thus, to answer the original question definitively, the mutant LR400 was crossed as a female parent with a N. plumbaginifolia line carrying streptomycin-resistant N. tabacum plastids. Calli were then induced from the seedlings. Occasional paternal plastid transmissions were selected as streptomycin-resistant calli on selective medium. These cell lines were shown by restriction enzyme analysis to contain paternal plastids and maternal mitochondria. They were tested for greening and growing ability in the presence of lincomycin. These resistance traits proved to be genetically linked and exclusively located in the plastids.
基于抗林可霉素的白花烟草质体突变体在选择性条件下于黑暗中生长的能力，人们认为它们也携带线粒体突变。为了阐明线粒体的作用，将绿色的、抗林可霉素的白花烟草突变体LR400的单个原生质体与烟草质体白化系92V37的原生质体进行微融合，92V37具有波叶烟草的细胞质。具有波叶烟草质体和重组线粒体的抗林可霉素白化胞质杂种系的产生，有力地表明了线粒体在林可霉素抗性中起决定性作用。然而，对LR400和其他几个抗林可霉素的白花烟草突变体的26S rRNA基因中包含假定突变位点的区域进行序列分析，结果显示与野生型序列没有差异。作为融合产物抗性的另一个来源，烟草融合亲本也被考虑在内。令人惊讶的是，检测到烟草具有天然的林可霉素抗性，该抗性作为显性核性状遗传。这一结果使上述融合数据的解释受到质疑。因此，为了明确回答最初的问题，将突变体LR400作为母本与携带抗链霉素烟草质体的白花烟草品系杂交。然后从幼苗中诱导愈伤组织。在选择培养基上，偶尔选择父本质体传递作为抗链霉素愈伤组织。通过限制性内切酶分析表明，这些细胞系含有父本质体和母本线粒体。对它们在林可霉素存在下的绿化和生长能力进行了测试。这些抗性性状被证明是遗传连锁的，并且仅位于质体中。
